No, she's not.
Terri, Kaine and Desiree have all suffered for having their son taken away. Terri has also suffered for being targeted by a police investigation that decided on their preferred culprit early and refused to rethink when the evidence pointed elsewhere, even when the Grand Jury failed to indict.
Everyone has suffered from the police's botched investigation and their refusal to hand the case over to the FBI despite having spent fourteen years and a lot of money and manhours with absolutely nothing to show for it but a series of embarrassments.
Kyron has certainly suffered for it. I believe that he is dead and was killed fairly quickly by the perpetrator, but if there was a sliver of a chance that he could have been saved, the police botched that too.
Kaine has always been clear that he believes Terri was responsible for Kyron's disappearance. So why would he have any reason to deny the hate emails? Why would he deny being briefed on the witnesses that saw Terri leave with Kyron? If they were true, they would bolster his claims.
Desiree, on the other hand, has every reason to spread these claims even if they're weak. She has by her own admission believed in Terri's guilt from day one and has resented her for almost a decade before if the Morris book is to be believed. Outside of these two, she has claimed Terri lied about last seeing Kyron because there was a wall that prevented her from seeing him from where she was - a wall that didn't exist, in a school Desiree had almost never visited at that time. She has put the worst possible spin on any statement Terri ever made, given claims we know to be false (that Terri was never in the dry cleaners) and even changed details when needed (in the book she insists Kyron was not supposed to be in the talent show, last year she insisted he was). All of these have in common that they are against Terri. It's understandable and hardly uncommon, that someone would believe and bolster claims that confirm what they already believe.
The problem is, of course, that in doing so she is not helping to find Kyron and may well be hindering. I don't place any blame on her, but rather her enablers - any lazy reporter or hack crime writer who doesn't bother to do a modicum of research into her claims, or this case for that matter. Desiree named the witnesses in the Morris book and elsewhere, yet I haven't seen anyone even admitting to an attempt to contact them for confirmation. Kyron isn't helped by swallowing anyone's claims at face value, not Terri's, not Kaine's, not Desiree's.